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Oct. 11, 2010 -- More than one-third of women with epilepsy may experience problems becoming pregnant, according to a new study of women from India. This rate is more twice as high as the infertility rate seen among Indian women in the general population.

The study is published in the Oct. 12 issue of Neurology.

There are many reasons that women with epilepsy may have difficulty conceiving, including the effects of certain drugs on hormones involved in pregnancy and facets of the disease itself or its severity.

The new study included 375 women with an average age of 26 who had epilepsy and were planning to start a family. They were followed for up to 10 years. During this time, 231 women became pregnant, and 144 women did not. Most pregnancies occurred within the first two years of attempting to conceive, the study researchers report.

More Epilepsy Drugs, Greater Infertility Risk

The more drugs the women were taking to control their epilepsy, the greater their risk for fertility problems. Women taking three or more drugs to treat their epilepsy were about 18 times more likely to experience fertility problems, compared with women who were not taking any epilepsy drugs.

Seven percent of women taking no drugs to control their seizures experienced fertility problems, compared with 32% of those taking one drug, 41% of those taking two drugs, and 60% of those taking three or more epilepsy medications, the study shows.

“This may be due to the adverse effects of taking multiple drugs or it could be a more indirect effect because people who are taking multiple drugs are more likely to have severe epilepsy that is difficult to treat,” the researchers conclude.

Older women and women with less than 10 years of education were also more likely to experience difficulty conceiving. Fertility risk was not tied to the type of epilepsy in the new study, the researchers report.

The study did have some limitations. For example, women with epilepsy who were trying to conceive were not compared to a group of women without epilepsy also trying to become pregnant.

Prepregnancy Counseling for Women With Epilepsy

Kimford Meador, MD, a professor of neurology at Emory University in Atlanta, says there have been studies with similar findings in England, but other studies have not found an increased risk for infertility among women with epilepsy. Meador is also on the advisory board of the Epilepsy Foundation.

"Women of childbearing age with epilepsy should have a conversation with their doctor even before they are contemplating pregnancy as half of all pregnancies are unplanned," he says. "You want to make sure you are on the right drug or drugs and that your seizures are controlled before you get pregnant," he says.

If your epilepsy is under control before pregnancy, you are less likely to have seizures during pregnancy, Meador says. "You don't need to see a fertility specialist right off the bat," he says. "Most women with epilepsy still can get pregnant even without fertility help, and the majority of babies are normal."

Talk to Your Neurologist

"Women with epilepsy are at increased risk for infertility," says Alison M. Pack, MD, a neurologist at Columbia University, who wrote an editorial accompanying the new study. "This study suggests that one potentially modifiable factor is being on multiple drugs, and avoiding the drug phenobarbital.”

In the new study, women taking phenobarbital were at greater risk for fertility issues. This drug is no longer widely used in the U.S.

"Women with epilepsy should be counseled that they are at risk for infertility," she says. "Should they all be sent to fertility specialists right away? No."

Pack recommends talking to your epilepsy doctor if you are thinking about becoming pregnant and working with your doctor to simplify your medication regimen as much as possible. "If it is taking longer than six months to conceive, it's not unreasonable to seek an evaluation from a fertility expert -- especially if you also have other risk factors for infertility such as advancing age."

Dileep Nair, MD, a neurologist at the Epilepsy Center at Cleveland Clinic in Ohio, agrees with Pack. "This study shows that if women with epilepsy are going to get pregnant, it tends to happen in the first two years of trying," he says.

This helps further identify a high-risk group of women. Don't waste time, he says. "If you have epilepsy and want to get pregnant, go to your neurologist and discuss your medications, so he or she can counsel you on the effects of these medications on your fertility and birth defects." Some epilepsy medications have been linked to birth defects.

Infertility Workup and Epilepsy

Eric Flisser, MD, a reproductive endocrinologist at Reproductive Medicine Associates in New York, says that the initial infertility workup is the same for women with epilepsy as it is for women without epilepsy. "We want to see you if you are under 35 and have been trying for a year. If you are older than 35, we recommend an evaluation after six months of trying."

"Everyone is screened in a similar fashion including semen analysis, a hysterosalpingogram or X-ray of uterus and fallopian tubes to check for blockages, and blood tests to measure hormone levels," Flisser tells WebMD.

"Just because a woman has epilepsy does not mean she doesn't also have common infertility problems," he says. "It is not clear why or if women with epilepsy have fertility problems, so we need to make sure we are not missing one of the simple things."

Certain epilepsy medications may affect fertility. "This should be discussed with your doctor before attempting to conceive," he says. In addition, some epilepsy medications also interfere with folic acid, which helps prevent neural tube defects. "You may need extra folic acid during pregnancy."